1. Field of the Invention
The present invention relates to an air pressure switching valve, and more specifically, to a manifold provided with two switching valves or more different in the number of ports or output type.
2. Description of the Related Art
Pneumatic apparatuses have been heretofore used in various fields of industry because of their low cost, labor saving and automation. Further, since air pressure can be always kept clean relative to environments, they are recently being used in the production line of semiconductors.
Particularly, in pneumatic apparatuses for automatic control, an air pressure switching valve which constitutes an important constituent portion uses an air pressure switching valve different in number of a plurality of ports. However, they are formed into a manifold due to the space saving, pipe saving, easiness of management, and the like.
FIGS. 34 and 35 show a first conventional embodiment of a manifold provided with a 3-port valve and a 5-port valve, which is an air pressure switching valve. FIG. 34 is a top view of the manifold, and FIG. 35 is a sectional view of a 5-port valve portion of the manifold. In FIG. 34, a manifold 200 is composed of a manifold base 201, 3-port valves 203a, 203b, and a 5-port valve 204.
The 3-port valve has two kinds, one being an NO type in which normally, an air port is communicated with an output port, the other being an NC type in which normally, an exhaust port is communicated with an output port. Since the exhaust port of the 3-port valve can be closed into a 2-port valve, the 2-port valve can be mounted.
In the manifold base 201, an air port 209a is formed in a connection surface with a 5-port valve or the like, as shown in FIG. 35. The manifold base 201 is formed with an air flowpassage 212 perpendicular to an air port such as a 5-port valve, the air port such as a 5-port valve being communicated with an air flowpassage 212. This provides a concentrated supply of air. The exhaust is discharged out of an exhaust port provided in each air pressure switching valve.
On the other hand, on the side of a connection surface with the manifold base 201 of the 5-port valve 204 are formed an air port 209b and two exhaust ports 207 and 208. A method for mounting the 5-port valve 204 on the manifold base 201 will be described hereinafter. The air port 209b formed in the 5-port valve 204 is connected to the air port 209a formed in the connection surface of the manifold base 201, and the 5-port valve 204 is mounted on the manifold base 201. A seal gasket 211 is mounted on a connection portion of the air port so as to prevent air from leaking out of the connection surface. The 3-port valves 203a and 203b can be also mounted on the manifold base 201 in a similar method.
Various pneumatically-operated apparatuses not shown are mounted on the output ports 205, 206 of the manifold 200 constructed as described above. Air having a predetermined pressure is supplied to the air flowpassage 212 from an air pressure supply apparatus not shown to operate the air pressure switching valve thereby operating various pneumatically-operated apparatuses.
However, the aforementioned manifold 200 had the following problem. Since the 3-port valve is different in size from the 5-port valve, the distance from the manifold base is disorderly. As a result, in case of an output port and a solenoid valve, a difference in level occurs in electric wiring portions, and pipes and wirings become complicated.
For solving the aforementioned problem, FIGS. 36 and 37 show a second conventional embodiment of a manifold in which a 3-port valve and a 5-port valve are provided on a manifold base mainly for a 5-port valve proposed. FIG. 36 is a top view of a manifold, and FIG. 37 is a sectional view of a 5-port valve portion of the manifold. As shown in FIG. 36, a manifold 220 is composed of a manifold base 221, 3-port valves 223a, 223b, and a 5-port valve 224. An exhaust port and an output port of the 5-port valve are closed one by one and used as a 3-port valve. Therefore, the 3-port valve is the same in dimension as that of the 5-port valve.
On the connection surface with the 5-port valve or the like of the manifold base 221 are formed an air port 229a, two exhaust ports 227a and 228a, and two output ports 225a and 226a, as shown in FIG. 37. The manifold base 221 is formed with an air flowpassage 232 and exhaust flowpassages 230 and 231 perpendicularly to the air port 229a and the exhaust ports 227a and 228a, and an air port and an exhaust port of the 5-port valve or the like are communicated with the air flowpassage 232 and the exhaust flowpassages 230 and 231. This can provide a concentrated supply of air and a concentrated discharge of air. In the case where clean environments are necessary in the industry of semiconductors, the manifold is large in dimension but a pilot exhaust as well as a concentrated exhaust are carried out.
On the other hand, on the connection surface with the manifold base 221 of the 5-port valve 224 are formed an air port 229b, two exhaust ports 227b and 228b, and two output ports 225b and 226b.
A method for mounting the 5-port valve on the manifold base will be described hereinafter. The air port 229b, the exhaust ports 227b, 228b and the output ports 225b, 226b formed in the connection surface of the 5-port valve 224 are connected to the air port 229a, the exhaust ports 227a, 228a and the output ports 225a, 226a formed in the connection surface of the manifold base 221, and the 5-port valve 224 is mounted on the manifold base 221. A seal gasket 233 is mounted on the connection portion of each port so as to prevent air from leaking out of the connection surface.
With respect to the 3-port valve, since the number of ports formed in the connection surface of the air pressure switching valve is different from that of ports formed in the connection surface of the manifold base, the 3-port valve is mounted on the manifold base after completion of the following work.
The NO type 3-port valve 223a and the NC type 3-port valve 223b are mounted on the manifold base 221 with the output port 226a and the output port 225a, respectively, closed.
Since the thus constructed manifold 220 is mainly constituted by the 5-port valve, the 5-port valve is mounted in the same direction with respect to the manifold base 221, and the distance from the manifold base 221 to the outside of the 5-port valve and the 3-port valve is constant. Further, since the output ports are also formed in the manifold base 221, pipes and wirings are completely arranged, this overcoming the problem noted in the aforementioned first conventional embodiment.
FIGS. 38, 39 and 40 show a third conventional embodiment of a manifold on which NO type and NC type 3-port valves can be mounted. Here, the NO type is of a flowpassage shape in which normally, an air port is communicated with an output port, and the NC type is of a flowpassage shape in which normally, an output port is communicated with an exhaust port. For example, in case of a solenoid valve, in the deenergized mode, the NO type is that an air port is communicated with an output port, and the NC type is that an output port is communicated with an exhaust port. FIG. 38 is a plan view of a manifold, FIG. 39 is a sectional view of an NO type 3-port valve portion of a manifold, and FIG. 40 is a sectional view of an NC type 3-port valve portion of a manifold. In FIG. 38, a manifold 300 is composed of a manifold base 301, an NO type 3-port valve 302 and an NC type 3-port valve 303.
In the manifold base 301, an air port 309a, an exhaust port 308a and an output port 307a are formed in the connection surface with the 3-port valve. Further, in the manifold base 301, an air flowpassage 304 and an exhaust flowpassage 305 are formed perpendicularly to an air port 309b and an exhaust port 308b of the 3-port valve, the air port 309b and the exhaust port 308b of the 3-port valve being communicated with the air flowpassage 304 and the exhaust flowpassage 305, respectively. This concentratedly processes supply and exhaust of air. Pilot exhaust is discharged from a pilot exhaust port 306 provided in the 3-port valve.
In the case where clean environments are necessary in the industry of semiconductors, the manifold is large in dimension, but the pilot exhaust is accomplished by concentrated exhaust.
On the other hand, on the connection surface side with the manifold base 301 of the 3-port valves 302 and 303 are formed an air port 309b, an exhaust port 308b and an output port 307b. The NO type 3-port valve 302 and the NC type 3-port valve 303 house therein different shapes of spools 310 and 311. An NO type flowpassage or an NC type flowpassage is determined depending on the shape of the spools.
A method for mounting the 3-port valves 302 and 303 on the manifold base 301 will be described hereinafter.
The air port 309b, the exhaust ports 308b and the output ports 307b formed in the connection surface of the 3-port valves 302 and 303 are connected to the air port 309a, the exhaust port 308a and the output port 307a formed in the connection surface of the manifold base 301, and the 3-port valves 302 and 303 are mounted on the manifold base 301. A seal gasket 312 is mounted on the connection portion of each port so as to prevent air from leaking out of the connection surface.
Various pneumatically-operated apparatuses not shown are mounted on the output port 307a of the manifold 300 constructed as described above. Air having a predetermined pressure is supplied to the air flowpassage 304 from an air pressure supply apparatus not shown to operate the air pressure switching valve thereby operating various pneumatically-operated apparatuses.
However, the aforementioned manifold 300 had the following problem. The NO type 3-port valve and the NC type 3-port valve are manufactured by changing the shape of the spools within the 3-port valve. In this case, since the number of parts increases in the production process, the cost increases accordingly. Further, a user must have two types of 3-port valves in order to change the flowpassages of NO type and NC type. This increases extra expenses for storage of 3-port valves not used, thus increasing an economical burden.
FIG. 41 shows a fourth conventional embodiment of a 3-port valve manifold proposed in order to overcome the problem noted above with respect to the third prior art. Here, with respect to the same shape of spools, that is, the same 3-port valve, the direction of the valve is changed whereby the change of flowpassage from the NO type to the NC type can be done. That is, in FIG. 41, 3-port valves 320a and 320b are the same article, and there are used 320a as the NC type 3-port valve, and 320b as the NO type 3-port valve. When the air port and the exhaust port when being used as the NO type are used as the NC type, they function as the exhaust port and the air port, respectively. Thereby, the problem encountered in the third prior art can be overcome by this manifold.
However, recently, when the air pressure switching valve is used at a place where high accuracy is required particularly such as the production line of semiconductors, the conventional manifolds pose the following problems.
First, in the second conventional embodiment, the 5-port valve is used in order to use the air pressure switching valve having two output ports. Therefore, if two output ports are necessary, the manifold is constituted by the 5-port valve as a main. Accordingly, the dimension of the manifold is so restricted by the shape dimension of the 5-port valve that cannot be further miniaturized. Therefore, in the case where it cannot be installed adjacent to working apparatuses, the connection line becomes long, bringing forth the lowering of a switching responsiveness. Further, since a dead space is present in the 3-port valve, it is difficult to further improve the responsiveness of the air pressure switching valve.
Even if the manifold is constituted mainly by the 4-port valve, the manifold base is small in dimension but since the 4-port valve is the same in outside diameter as that of the 5-port valve, the manifold cannot be miniaturized.
Second, since pilot air is supplied from the main source, a combination of air pressure and vacuum cannot be used as a working fluid. If a combination of air pressure and vacuum is used, an external pilot is necessary. Further, for concentratedly processing pilot air, the manifold requires an air port and an exhaust port for pilot air, further increasing the dimension of the manifold.
Third, in the fourth conventional embodiment, the direction of the whole valve is changed by 180 degrees in order that the change of flowpassages of NO type and NC type is carried out by one and the same 3-port valve. Therefore, a pilot air control valve is reversed in position to pose a problem in that the dimension of the manifold becomes large. Further, in the case where a concentrated supply of pilot air is carried out in the manifold, two pilot air ports are necessary in a 3-port valve.
This problem encountered in the fourth conventional embodiment can be overcome by the third conventional embodiment. That is, the problems of the respective conventional embodiments are contrary to each other.